Mold for Vulcanizing a Tire, a Method of Vulcanizing a Green Tire Blank, and a Tire Obtained by said Method

ABSTRACT

A mold includes at least one axial member carrying at least one sidewall molding surface for molding a sidewall of a tire, radial segments each carrying at least one surface for molding a tread of the tire and locking surfaces for connecting the axial member with the radial segments. First radial and axial locking surfaces which are displaceable and carried by the axial member cooperate with second radial and axial locking surfaces. The sidewall molding surface is integral with a fixed portion of the axial member. The first radial and axial locking surfaces are integral with at least one locking member mounted in the axial member and are movable relative to the fixed portion.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/982,503 which was filed with the U.S. Patent and Trademark Office onNov. 1, 2007. Priority is claimed for this invention and application,corresponding application(s) having been filed in France on Nov. 2,2006, No. 06/54700, USA on Jan. 18, 2007, No. 60/881,074.

FIELD OF THE INVENTION

The present invention relates to a mold for vulcanizing a tire, to amethod of vulcanizing a green tire blank and to a tire obtained by saidmethod.

BACKGROUND OF THE INVENTION

In the present text, reference to the “axis” of a tire is a reference toits axis of revolution. Said axis defines an axial direction of the moldassuming that the tire is in the mold.

Fabricating a tire by vulcanizing a green tire blank is known. To thisend, the blank is placed in a mold of the type comprising:

-   -   at least one axial member carrying at least one surface for        molding a sidewall of a tire;    -   radial segments each carrying at least one surface for molding a        tire tread; and    -   means for connecting the axial member with the radial segments,        comprising first radial and axial locking surfaces carried by        the axial member which can cooperate with second radial and        axial locking surfaces, which are complementary to the first        locking surfaces, carried by each radial segment, the first and        second locking surfaces being displaceable relative to each        other, between:        -   an open position of the mold in which the complementary            locking surfaces are separated; and        -   a closed position of the mold in which the complementary            locking surfaces cooperate with each other.

A mold of said type comprises first and second axial membersrespectively carrying surfaces for molding the first and second tiresidewalls and is described, for example, in European patent EP-A1-0 436495.

Normally, in order to vulcanize a green tire blank, said blank is placedin a mold of the above-mentioned type in the following manner.

Initially, the blank is placed in contact with the axial members, theneach axial member is connected with the radial segments, in particularby axially displacing the first and second locking surfaces relative toeach other between the open and closed positions of the mold.

Generally, in a conventional mold, the green blank is pressed againstthe molding surfaces of the axial members and radial segments of themold using a pressurized flexible membrane cooperating with the innersurface of the blank. In the mold disclosed in EP-A1-0 436 495, thepressure of the membrane, which is necessary in order to mold a tire,also has the effect of stressing the complementary locking surfaces intheir cooperation position, and thus keeping the mold closed. Since themolding pressure participates in locking the mold closed, theconventional mold is said to be self-locking.

However, in a mold of the above-mentioned type, the sidewall moldingsurfaces, carried by the first and second axial members, are integralwith the first radial and axial locking surfaces, also carried by thefirst and second axial members. For this reason, axial displacement ofthe first and second locking surfaces relative to each other whenclosing and opening the mold causes relative displacement between thesidewall molding surfaces which are integral with the first lockingsurfaces and the surfaces for molding the tread carried by the radialsegments. Said relative displacement causes the formation of an unwantedimpression on each sidewall of the blank before it is vulcanized, byplastic deformation of said sidewall.

SUMMARY OF THE INVENTION

The invention is provided to avoid the formation of unwanted impressionson the sidewalls of said blank before vulcanizing the green blank.

To this end, the invention provides a mold of the type comprising:

-   -   at least one axial member carrying at least one surface for        molding a sidewall of a tire;    -   radial segments each carrying at least one surface for molding a        tire tread;    -   means for connecting the axial member with the radial segments,        comprising first radial and axial locking surfaces carried by        the axial member which can cooperate with second radial and        axial locking surfaces, which are complementary to the first        locking surfaces, carried by each radial segment, the first and        second locking surfaces being displaceable relative to each        other, between:        -   an open position of the mold in which the complementary            locking surfaces are separated; and        -   a closed position of the mold in which the complementary            locking surfaces cooperate with each other; wherein each            sidewall molding surface integral with a fixed portion of            the axial member, the first locking surfaces being integral            with at least one locking member mounted in the axial member            and being movable relative to the fixed portion.

Since the first locking surfaces are movable relative to each sidewallmolding surface, when closing of the mold, displacement of said firstlocking surfaces does not cause displacement of the sidewall moldingsurface and does not cause the formation of an impression on the greenblank.

In a further, optional characteristic of the mold of the invention, thelocking member is mounted in the axial member to be axially displaceablerelative to the fixed portion between the open and closed positions ofthe mold.

Preferably, the first radial and axial locking surfaces are formed byannular grooves and ribs provided in the locking member, and the secondradial and axial locking surfaces are formed by annular groove segmentsand rib segments provided in each radial segment.

Said grooves and ribs, which are easy to produce, co-operate effectivelywith one another so as to lock each axial member radially and axiallywith the radial segments.

In a further, optional, characteristic of the mold of the invention, theaxial member includes at least one member for wedging the locking memberin the closed position of the mold.

Thus, by preventing the locking member from returning to the openposition of the mold when vulcanizing the tire, the wedging member holdsthe complementary locking surfaces in their cooperating position andthus keeps the mold closed.

In accordance with a further optional characteristic of the mold of theinvention, the wedging member is radially displaceably mounted in ahousing provided in the fixed position of the axial member, between:

-   -   a retracted position in the housing; and    -   a wedged position in which the wedging member is inserted        between an axial surface of the fixed portion, extending said        housing, and an axial end surface of the locking member.

The retracted position of the wedging member allows axial displacementof the locking member between its mold open and closed positions. Thewedging position of the wedging member prevents the locking member fromreturning to the open position of the mold, thus keeping the moldclosed.

In accordance with a further optional characteristic of the mold of theinvention, the wedging member is radially displaceably mounted on anouter axial end surface of the fixed portion of the axial member,between:

-   -   a disengaged position of the locking member; and    -   a wedging position in which the wedging member is inserted        between said outer surface and an axial surface to wedge the        locking member.

Said wedging member is readily accessible from the outside of the mold.In the disengaged position, the wedging member may be separated from themold and allows axial displacement of the locking member between itsmold open and closed positions.

In accordance with a further optional characteristic of the mold of theinvention, the wedging member has the general form of a ring which iscoaxial with the tire, the locking member comprising axial projectionswhich are circumferentially distributed, alternating with axialindentations, the wedging member comprising projections and indentationswhich are complementary with the projections and indentations of thelocking member, the locking member and the wedging member being movablerelative to each other between:

-   -   a position in which the projections of the locking member and        the wedging member are axially superimposed; and    -   a position in which the projections of the locking member and        the wedging member are fitted into complementary indentations of        the wedging member and locking member respectively.

By these means, the thickness of the assembly formed by the lockingmember and wedging member varies so that when the projections areaxially superimposed, the mold is in the closed position.

According to another optional characteristic of the mold of theinvention, the locking member is mounted in the axial member to bedisplaceable in rotation relative to the fixed portion between the openand closed positions of the mold.

Preferably, the first locking surfaces are designed to co-operate withthe second locking surfaces in compliance with a bayonet typeconnection,

-   -   the first radial and axial locking surfaces being formed by an        annular surface formed in the locking member, provided with        axial projections that are circumferentially distributed over a        radially outer portion of said annular surface;    -   the second radial and axial locking surfaces being formed by        annular surface segments each provided in a corresponding radial        segment, each annular surface segment being provided with axial        projections distributed circumferentially over a radially inner        portion of the annular surface segment; and    -   the projections alternating with indentations.

Such locking surfaces for co-operating with one another producing abayonet type connection occupy little space axially and do not requirean additional wedging member.

According to another optional characteristic of the mold of theinvention, the locking member has the general form of a ring that iscoaxial with the tire, assuming that the tire is in the mold.

Such a locking member is easy to guide axially or in rotation over thestationary portion of the axial member.

In accordance with another optional characteristic of the mold of theinvention, said mold comprises first and second axial membersrespectively carrying surfaces for molding the first and second tiresidewalls, the first locking surfaces being integral with at least onelocking member mounted in each axial member and being movable relativeto the fixed portion of said axial member.

The invention also provides a method of vulcanizing a green tire blankusing a mold comprising:

-   -   at least one axial member carrying at least one surface for        molding a sidewall of a tire;    -   radial segments carrying at least one surface for molding a        tread of a tire;    -   means for connecting the axial member with the radial segments;        the method being of the type in which:    -   the green blank is placed in contact with the axial member; then    -   said axial member is connected with the radial segments using        the connection means;        wherein since the mold is as defined above, the axial member is        connected with the radial segments using connection means by        displacing the first and second locking surfaces relative to        each other from an open position towards a closed position of        the mold, while keeping the axial position of the fixed portion        of the axial member constant relative to the radial segments.

Since the axial position of the fixed portion of the axial memberrelative to the radial segments remains constant during axialdisplacement of the first and second locking surfaces relative to eachother, there is no relative displacement between each sidewall moldingsurface integral with the fixed portion of the axial member and eachtread molding surface carried by the radial segments. Thus, no unwantedimpressions are formed on the sidewalls of the green tire blank.

In accordance with another optional characteristic of the method of theinvention, with the mold as described above, after having axiallydisplaced the first and second locking surfaces relative to each otherfrom the open position towards the closed position of the mold, thelocking member is wedged in the closed position of the mold by radialdisplacement of the wedging member.

Like the pressure of the membrane in a conventional mold, the wedgingmember can stress the complementary locking surfaces into theircooperation position and thus keep the mold closed.

The invention also provides a tire, the tire being obtained by a methodas defined above.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood from the following descriptionmade solely by way of non-limiting example made with reference to theaccompanying drawings, in which:

FIG. 1 is an axial section of a mold in accordance with a firstembodiment of the invention;

FIGS. 2 to 4 are half views analogous to FIG. 1, showing the mold atdifferent stages of closing;

FIG. 5 is an axial sectional half view of a mold in accordance with asecond embodiment of the invention;

FIG. 6 is an axial sectional half view of a mold in accordance with athird embodiment of the invention;

FIGS. 7 to 9 are perspective views of a portion of the locking memberand wedging member of the mold of FIG. 6 at different stages of closingthe mold;

FIGS. 10 and 11 are half-views in axial section of a mold in accordancewith a fourth embodiment of the invention shown respectively closed andopen; and

FIGS. 12 and 13 are perspective views of a portion of a radial segmentand of the locking member of the mold of FIGS. 10 and 11.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIGS. 1 to 4 show a mold in a first embodiment of the invention, denotedby the general reference numeral 10. Said mold 10 is intended forvulcanizing a blank to obtain a tire 12 which is shown only in FIG. 1.

In the example described, the mold 10 is generally a body of revolutionabout an axis X which coincides with the axis of revolution of the tire12 when the tire is housed in the mold 10, as shown in FIG. 1.

The mold includes first and second axial members 14, radial segments 16and means 18 for connecting each axial member 14 with the radialsegments 16.

Each axial member 14 is generally a body of revolution and carries asurface of revolution 20 to mold a corresponding sidewall 22 of thetire. The radial segments 16 each carry a segment of a surface ofrevolution 24 to mold a tread 26 of the tire 12.

Each axial member 14 comprises a fixed portion 14F termed a shell and aportion 14M, termed the movable portion, which is axially movablymounted relative to the fixed portion 14F.

In the example described, the movable portion 14M is in the generalshape of a ring which is coaxial with the tire 12 assuming that the tire12 is in the mold 10. The movable portion 14M is axially defined by thefirst, SI, and second, SE, end surfaces (see FIG. 4). The movableportion 14M is axially guided relative to the fixed portion 14F by meansof complementary cylindrical axial guiding surfaces 28, 30, allowingaxial displacement of the movable portion 14M relative to the fixedportion by sliding.

It should be noted that the sidewall molding surface 20 of each axialmember 14 is integral with the fixed portion 14F of said member 14.

The fixed portion 14F of each axial member 14 includes a shoulder 32which can cooperate with a complementary shoulder 34 of each radialsegment 16. Said complementary shoulders 32, 34 form complementarysurfaces for axially bearing and mutually radially guiding the axialmember 14 with each radial segment 16.

The connection means 18 comprise first radial and axial locking surfacesformed by annular grooves 36 and ribs 38 (see FIG. 2) provided in themovable portion 14M of the axial member. The first locking surfaces 36,38 are thus integral with the movable portion 14M, the movable portionforming a locking member.

The annular grooves 36 and ribs 38 cooperate with complementary annulargroove 40 and rib 42 segments formed in each radial segment 16 toradially and axially lock each axial member 14 with the radial segments16.

The first locking surfaces 36, 38 carried by each axial member 14 canthus cooperate with second radial and axial locking surfaces which arecomplementary to said first locking surfaces, formed by the annulargroove 40 and rib 42 segments integral with each radial segment 16.

Thus, the first 36, 38 and second 40, 42 locking surfaces are axiallydisplaceable relative to each other between:

-   -   an open position of the mold, as shown in FIGS. 2 and 3, in        which the complementary locking surfaces 36 to 42 are separated;        and    -   a closed position of the mold, as shown in FIGS. 1 and 4, in        which the complementary locking surfaces 36 to 42 cooperate with        each other.

The movable portion 14M and the first locking surfaces 36, 38 carried bysaid movable portion 14M can thus be axially displaced between the openand closed positions of the mold respectively shown in FIGS. 2 and 3 andin FIGS. 1 and 4.

Each axial member 14 comprises at least one member 44 for wedging themovable portion 14M in the closed position of the mold, as shown in FIG.1.

In the first embodiment of the invention shown in FIGS. 1 to 4, thewedging member 44 is radially displaceably mounted in a housing 46provided in the fixed portion 14F of the axial member 14, between:

-   -   a retracted position in the housing 46, as shown in FIGS. 2 to        4; and    -   a wedging position as shown in FIG. 1.

In the wedging position, the wedging member 44 is inserted between anaxial surface 48 of the fixed portion 14F, extending the housing 46, andthe axial end surface SI of the movable portion 14M.

The principal aspects of a method of vulcanizing a green tire blankusing a mold 10 in accordance with the first embodiment of the inventionwill now be described.

Firstly, the green tire blank is placed between the two axial members 14of the mold 10 so that said blank is in contact with said axial members14, while the radial segments 16 are radially spaced from the axialmembers 14, as shown in FIG. 2.

Next, while each wedging member 46 is in the retracted position in thehousing 46 and each movable portion 14M is in the open position of themold 10, the radial segments 16 are moved radially closer to the axialmembers 14 into the position shown in FIG. 3. On moving, thecomplementary shoulders 32, 34 participate in mutually radially guidingeach axial member 14 with each radial segment 16.

Next, the movable portion 14M of each axial member 14 is axiallydisplaced towards the closed position of the mold 10 as shown in FIG. 4,using conventional means.

This has the effect of axially displacing the first 36, 38 and second40, 42 locking surfaces relative to each other, from the open positiontowards the closed position of the mold 10 and, as a result, connectingthe axial member 14 to the radial segments 16.

It should be noted that the relative axial displacement of the first 36,38 and second 40, 42 locking surfaces is carried out while keeping theaxial position of the fixed portion 14F of each axial member 14 constantrelative to the radial segments 16.

Finally, the movable portion 14M of each axial member 14 is wedged inthe closed position of the mold 10 by radial displacement of the wedgingmember 44 from its retracted position towards its wedging position shownin FIG. 1.

FIG. 5 shows a mold in accordance with a second embodiment of theinvention. In FIG. 5, elements analogous to those shown in FIGS. 1 to 4are denoted by identical reference numerals.

In this embodiment, the vulcanizing member 44 is radially displaceablymounted on an axial outer end surface S′E of the fixed portion 14F ofthe axial member 14, between:

-   -   a disengaged position of the movable portion 14M forming the        locking member; and    -   a wedging position as shown in FIG. 5, in which the wedging        member 44 is inserted between said outer surface S′E and a        radially inner shoulder of the movable portion 14M forming an        axial wedging surface SC on said movable portion 14M.

The wedging member may have the general form of a segmented ring coaxialwith the axis X of the mold.

The principal aspects of a method of vulcanizing a green tire blankusing a mold 10 in accordance with the second implementation of theinvention can be deduced mutatis mutandis from the method describedabove with the mold 10 in accordance with the first implementation ofthe invention.

FIG. 6 shows a mold in accordance with a third embodiment of theinvention. In said FIG. 6, elements analogous to those shown in FIGS. 1to 5 are denoted by identical reference numerals.

In this third embodiment, the locking member 14M includes axialprojections 62B which are circumferentially distributed, alternatingwith axial indentations 64B.

The wedging member 44 is in the general shape of a ring which is coaxialwith the tire and includes projections 62C and indentations 64C whichare complementary to the projections 62B and indentations 64B of thelocking member 14M.

The locking member 14M and wedging member 44 are movable relative toeach other between:

-   -   a position wherein the projections 62B and 62C of the locking        member 14M and wedging member 44 are axially superimposed; and    -   a position wherein projections 62B and 62C of the locking member        14M and wedging member 44 are fitted into the complementary        indentations 64C and 64B of the wedging member 44 and locking        member 14M respectively.

The principal aspects of a method of vulcanizing a green tire blankusing a mold in accordance with the third embodiment of the inventionwill now be described.

Once the green tire blank has been placed between the two axial members14 of the mold, the locking member 14M is axially displaced from thefitting position shown in FIG. 7 towards an intermediate position inwhich the projections 62B and 62C are respectively axially offsetrelative to the indentations 64C and 62C. This intermediate position isshown in FIG. 8.

Next, the locking member 14M is pivoted relative to the wedging member44 about the tire axis to reach the superimposed position shown in FIG.9, corresponding to the mold closing position.

A variant of this embodiment could be to use a screw-and-nut connectionbetween the fixed and movable portions 14F and 14M of the axial member,with displacement by tightening or loosening the screw connectionincluding an axial component.

FIGS. 10 to 13 show a mold in accordance with a fourth embodiment of theinvention. In these figures, elements analogous to those shown in FIGS.1 to 9 are designated by identical references.

In this fourth embodiment, the movable portion 14M (locking member) ofeach axial member 14 of the mold is mounted to move in rotation aboutthe axis X on the fixed portion 14F of said axial member 14.

The movable portion 14M is generally in the form of a ring mounted onthe same axis as the tire 12, assuming that the tire 12 is in the mold10. The movable portion 14M is guided in rotation relative to the fixedportion 14F in particular with the help of complementary cylindricalguide surfaces 66 and 70. Unlike the above-described embodiments, themovable portion 14M is not designed to be displaced axially relative tothe fixed portion 14F.

In the fourth embodiment, the first radial and axial locking surfaces ofthe connection means 18 are formed by an annular surface 72 provided inthe movable portion 14M of the axial member and provided with axialprojections 74A distributed circumferentially over a radially outerportion of said annular surface 72 (see FIGS. 10, 11, and 13). Theseprojections 74A alternate with indentations 76A.

Furthermore, the second radial and axial locking surfaces, complementaryto the first locking surfaces, are formed by annular surface segments78, each provided in a corresponding radial segment 16. Each annularsurface segment 78 is provided with axial projections 80B distributedcircumferentially over a radial inner portion of the segment of theannular surface 78 (see FIGS. 10, 11, and 12). These projections 80Balternate with indentations 82B.

The first locking surfaces 72, 74A carried by each axial member 14 aredesigned to co-operate in a bayonet type connection with the secondlocking surfaces 78, 80B of each radial segment 16.

By causing the movable portion 14M to turn relative to the fixed portion14F, the first locking surfaces are displaced in rotation relative tothe second locking surfaces between:

-   -   a position in which the projections 74A, 80B are mutually        angularly offset, allowing these projections 74A, 80B to move        radially relative to one another through the complementary        indentations 76A, 82B; and    -   a position in which the projections 74A, 80B are put into mutual        radial abutment, in which the projections 74A of each movable        portion 14M surround the corresponding projections 80B of the        radial segments 16.

In the angularly offset position of the projections 74A, 80B, the axialmembers 14 can be separated from the radial segments 16 so that the mold10 is open, as shown in FIG. 11.

In the radial abutment position of the projections 74A, 80B, the axialmembers 14 and the radial segments 16 are prevented from moving radiallyand axially relative to one another, such that the mold 10 is closed, asshown in FIG. 10.

In a manner analogous to the above-described embodiment, starting fromthe configuration of the mold shown in FIG. 11 (mold 10 open), in orderto close the mold, the radial segments 16 are moved radially closer tothe axial members 14 until the position shown in FIG. 10 is reached.

During this approach, the movable portion 14M is in its position inwhich the projections 74A, 80B are mutually angularly offset, thusallowing these projections 74A, 80B to be radially displaced relative toone another through the complementary indentations 76A, 82B.Furthermore, the complementary shoulders 32, 34 contribute to mutualradial guidance of the axial members 14 and the radial segments 16.

Thereafter, the movable portion 14M is caused to turn so as to be placedin its position in which the projections 74A, 80B are in radial abutmentagainst one another, thus having the effect of locking the axial members14 and the radial segments 16 both radially and axially.

The invention is not limited to the embodiments described above.

1. A mold for vulcanizing a tire, the mold comprising: at least oneaxial member carrying at least one sidewall molding surface for moldinga sidewall of a tire; radial segments each carrying at least one surfacefor molding a tire tread; means for connecting the at least one axialmember with the radial segments, the connection means comprising firstradial and axial locking surfaces carried by the at least one axialmember and operable to cooperate with second radial and axial lockingsurfaces carried by each radial segment, the first and second radial andaxial locking surfaces being complementary to each other anddisplaceable relative to each other between an open position and aclosed position of the mold; wherein the complementary locking surfacesare separated in the open position of the mold and cooperate with eachother in the closed position of the mold; wherein the complementarylocking surfaces, when in the closed position, can be kept in the closedposition under the sole effect of internal pressure of the mold; whereinthe at least one sidewall molding surface is integral with a fixedportion of the at least one axial member, the first radial and axiallocking surfaces being integral with at least one locking member mountedin the at least one axial member and being movable relative to the fixedportion; wherein the at least one locking member has a first lockingmember mounted in the at least one axial member to be displaceable inrotation relative to the fixed portion between the open and closedpositions of the mold; wherein the first locking member includes thefirst radial and axial locking surfaces, which are configured tocooperate with the second radial and axial locking surfaces incompliance with a bayonet type connection; wherein the first radial andaxial locking surfaces are formed by an annular surface formed in thefirst locking member, provided with first axial projections that arecircumferentially distributed over a radially outer portion of saidannular surface; wherein the second radial and axial locking surfacesare formed by annular surface segments each provided in a correspondingradial segment, each of the annular surface segments being provided withsecond axial projections distributed circumferentially over a radiallyinner portion of the respective annular surface segment; and wherein theprojections alternate with indentations.
 2. The mold according to claim1, in which the at least one locking member has a second locking membermounted in the at least one axial member to be axially displaceablerelative to the fixed portion between the open and closed positions ofthe mold.
 3. The mold according to claim 2, in which the second lockingmember has third radial and axial locking surfaces formed by annulargrooves and ribs provided in the second locking member, and in which theradial segments have fourth radial and axial locking surfaces formed byannular groove segments and rib segments.
 4. The mold according to claim2, in which the at least one axial member includes at least one wedgingmember of the second locking member for locking the mold in the closedposition.
 5. The mold according to claim 4, in which the wedging memberis radially displaceably mounted in a housing provided in the fixedportion of the at least one axial member, between: a retracted positionin the housing; and a wedged position in which the wedging member isinserted between an axial surface of the fixed portion, extending saidhousing, and an axial end surface of the second locking member.
 6. Themold according to claim 4, in which the wedging member is radiallydisplaceably mounted on an outer axial end surface of the fixed portionof the at least one axial member, between: a disengaged position of thesecond locking member; and a wedging position in which the wedgingmember is inserted between said outer surface and an axial surface towedge the second locking member.
 7. The mold according to claim 4, inwhich the wedging member has a general form of a ring which is coaxialwith the tire, the second locking member comprising axial projectionswhich are circumferentially distributed, alternating with axialindentations, the wedging member comprising projections and indentationswhich are complementary with the axial projections and axialindentations of the second locking member, the second locking member andthe wedging member being movable relative to each other between: aposition in which the axial projections of the second locking member andthe projections of the wedging member are axially superimposed; and aposition in which the axial projections of the second locking member andthe projections of the wedging member are fitted into complementaryindentations of the wedging member and the second locking member,respectively.
 8. The mold according to claim 1, in which the lockingmember has a general form of a ring which is coaxial with the tire whenthe tire is in the mold.
 9. The mold according to claim 1, in which theat least one axial member includes first and second axial membersrespectively carrying surfaces for molding the first and secondsidewalls of the tire, the first radial and axial locking surfaces beingintegral with the at least one locking member mounted in each of thefirst and second axial members and being movable relative to the fixedportion of each of the first and second axial members.
 10. A method ofvulcanizing a green tire blank using the mold according to claim 1, themold comprising: at least one axial member carrying at least one surfacefor molding a sidewall of a tire; radial segments carrying at least onesurface for molding a tread of the tire; and means for connecting the atleast one axial member with the radial segments; the method comprising:placing the green blank in contact with the at least one axial member;and connecting said at least one axial member with the radial segmentsusing the connection means; wherein the step of connecting the at leastone axial member with the radial segments is carried out by displacingthe first and second radial and axial locking surfaces relative to eachother from the open position towards the closed position of the mold,while keeping an axial position of the fixed portion of the at least oneaxial member constant relative to the radial segments.
 11. The methodaccording to claim 10, in which the at least one axial member includesat least one wedging member of the locking member for locking the moldin the closed position, and, after having axially displaced the firstand second radial and axial locking surfaces relative to each other fromthe open position towards the closing position of the mold, the lockingmember is wedged in the closed position of the mold by radialdisplacement of the wedging member.